Currently in testing and coming soon!
In the SalesLogix 7.5.1 Web client we found an issue with breaks in group members when there are multiple per-Account group members. The extra rows are reserved but not displayed. This is a known issue, defect number 69077. The issue will be fixed with Hot Fix 6, which is currently in external testing. The LAN client does not display this behavior.
If you are using SLX v7.5.1 Web and have experienced this issue there will be a fix soon!
-Brianna